Paint and varnish remover



* meant a sates.

CABLE-TON ELLIS, 0F MONTCLAIR, NEW JERSEY, ASSIGNOR '10 CELOID CEE'EICA COMPANY, A CORPORATION OF WEST VIRGINIA.

PAINT AND VAR-WISH REMOVEIR.

No Drawing.

To all whom it may concern: Be it known that I, CARLETON ELLIS, a citizen of the United States, residing in the city of Montclair, State of New Jersey, have invented certain new and useful Improvements in Paint and Varnish Removers, which is set forth in the following specification.

This invention relates to a composition adapted for use as a paint and varnish re- 1 mover and relates especially to a composition having a relatively high flashpoint and being of a substantially non-inflammable character or of such a low degree of inflammability that the composition may be used safely even in the neighborhood of a flame.

BenaoZ-acetone remooera-The paint and varnish removers commonly used at the present time are made up of benzol, acetone and wax and-have highly inflammable properties. If a large surface coated with such a remover is accidentally ignited a dangerous fire may ensue. The powerful action of a mixture of benzol and acetone has however established a standard of efficiency and rapidity of softening of paint and varnish which is diflicult to approach by any other combination of commercial solvents.

Penetrating and loosening action-A paint and varnish remover should have a powerful penetrating and losening action on dried coats of paint or varnish and should not dry out quickly, allowing time for the removal of the softened paint by means of a brush or putty knife or in other Ways. Such a solvent must be capable of general use, that is must have a removing action on all kinds of paint and varnish so that one grade of remover will serve the painter in all his operations of this character. Almost without exception the best removing effects are secured by light highly volatile solvents, these have not only a better penetrating ac- Serial No. 458,051.

the varnish to a jelly like easily removable film. In preparing a non-inflammable paint and varnish remover, which, other than its non-inflammability, has characteristics in common with the benzol acetone removers mentioned above is difiicult as the number of solvents available commercially which may be used in such composition is relatively limited if heavy solvents are excluded.

Non-inflammabihty.The use of the term non-inflammable as referred to herein does not mean necessarily that the composition cannot be ignited under severe test conditions but that it does not ignite readily so that an entire surface coated with the remover Will burst into flame on the application of a match. What is particularly meant by the term as used herein is that the composition in question when spread out on a surface and the flame of a match applied will not burst into instant ignition but in some cases may be ignited locally by superheating the surface through a prolonged application of the flame. Or if the surface is roughened and rolled up as for example by running a putty knife through the softened mass and a lighted match is brought in contact with a projection of the varnish film this may burn slowly for a time and then the flame will go out or it may. even spread slowly and gradually as the surface becomes heated. The rolled up varnish in this case probably acts to some extent as a wick. On the other hand the composition may have a higher degree of non-inflammabillty such that on contact with a flame no flash or ignition of any kind occurs the flame of the match being extinguished when lighted end is pressed down into the liquid. Intermediate these two is a grade which cannot be ignited when the remover is poured out on a flat surface and touched with a lighted match but on a vertical surfaceand by slight superheating ignition may be started and will travel upwardly along-the vertical layer of remover.

Film formation-In order to use a vola-' tile solvent or mixture of volatile solvents tion but seemingly soften the surface and convert it into a jelly-like material which is readily removed. On the other hand heavy q solvents which are much less volatile as a general rule have little penetratingpower and action being quite sluggish in most cases effectively it is necessar to have a retarder and not usually being capable of softening of evaporation. Para n wax 18 best for this urpose, the hardest wax being most suitable. The wax forms a skin over the surface of the volatile solvents so that evaporation is very greatly reduced in amount and will allow the solvents to perform their softening action. The manner in which a waxy film forms depends upon the amount of wax and the nature of the solvent. If a high proportion of a wax solvent is present too great a quantity of wax will be dissolved thereby diluting the remover with inert material and reducing the amount of actual solvent material available.

Odor.-Painters are accustomed to work with certain paint and varnish solvents such as turpentine, naphtha, gasoline and alcohol and do not take kindly to solvents which have odor which differ very greatly from these. It is important in a commercial article to have the preparation possess an odor agreeable to the painter or at least one which he will not object toto such an extent as to refuse to employ the product. It is also desirable that the remover be free from any highly objectionable odor such that when used, for example, in apartment houses the odor does not penetrate through the hallways to difierent apartments and cause complaint.

Uorrosice action-A composition which has a corrosive action .on the skin or which would stain the wood or raise the grain of the latter or which would corrode the tin cans ordinarily used as containersfor products of this description is objectionable.

U0nsisten0y.-The consistency of the remover should, as far aspossible, remain constant with the changes in temperature and not become a dense solid mass in the cold and a thin rapidly evaporating liquid at higher climatic temperatures.

Availability of raw material-The raw materials employed should be commercially available and should be fairly low in price as the cost of removing paint and varnish by such solvent material must not exceed that ofif the old methods of scraping or burn- H1 0 n the type of remover embodied in the present invention light volatile solvents are made the basis of the composition, although the addition of heavy solvents is not precluded and these light volatile solvents preferabl comprise a non-inflammable chlorinated ydrocarbon preferably trichlorethylene, although tetrachlorethane or acetylene tetrachloride, carbon tetrachloride etc. may also be used in some cases. Carbon tetrachloride, generallyspeaking, is not. recommended in compositions containing water on account of the decomposition of the tetrachloride in the presence of moisture causing an acid reaction and if the composition is in a tin can the latter will be attacked and leakage results. Trichlorethylene is much less likely to become acid and has a pleasanter odor than for example acetylene tetrachloride. The composition has a high flashpoint or degree of non-inflammability such that it is safe to use in the neighborhood of a flame and cannot be ignited by sparks, lighted cigarettes etc. A good degree of film formation with not an excessive amount of wax is obtained. The odor while noticeable is not of a disagreeable nature and after the operator has used the composition for a time the odor will be found unobjectionable to most persons.

A formula affording a composition having fair softening and penetrating qualities coupled with a not unpleasant odor is made by mixing 60 parts by volume of trichlorethylene, 25 parts of ethyl acetate and 15 parts of monochlorbenzol. To this is added from 7 to 15 per cent of hard paraffin wax. The proportion of trichlorethylene in this composition is considerable and being a pronounced wax solvent a somewhat larger proportion of wax is used than in some of the following compositions. Trichlorethylene does not have quite as strong an inflammability suppressing power as carbon tetrachloride, but, as stated, it is more desirable on account of odor and comparative freedom from action on metal surfaces. The inflammability suppressing power is dependent to a considerable extent on the vapor tension of the solvent and is more or less correlated with the boiling point. For example acetone boiling at 56 C. is not so suitable for use in the present composition because it takes in the neighborhood of 90 volumes of trichlorethylene to 10 volumes of acetone to sufficiently repress the inflammability of the latter. Thus such a composition would not very well serve as a paint and varnish remover because there would be an insuflicient amount of softening agent, namely the acetone and such a high proportion of Wax solvent that excessive amounts of wax would have to be employed. On the other hand when the boiling point is above C. and preferably above C. a more substantial amount of the softening agent may be utilized. Thus in the case of ethyl acetate boiling at 77 C. in the neighborhood of 25 per cent may be used and the same is true of methyl ethyl ketone boiling at 79 C. Such mixtures are diflicult to ignite with a flame and the combustion as a rule does not continue or spread from the superheated portion at the place of ignition.

The addition of heavy solvents in small quantity up to 30% or more in some cases improves the degree of non-inflammability and aids in keeping the composition moist over a considerable period of time so that for example a surface to which remover has been applied in the afternoon will keep moist over night so that the finish may be removed on the following morning. Examaaeaioi ples of heavy solventsor solvents which are relatively heavy in comparison with some of the light penetrating solvent material preferably employed, are compounds such as aniline, toluidine, xylidine, phenol or carbolic acid, cresol and cresylic acid and higher phenols. Also what is commercially known as tar acids and is usually a mixture of cresols and higher phenols but does not contain phenol itself. The dichlorbenzols are heavy non-inflammable bodies, the paradichlorbenzol being solid while the ortho compound is liquid. The latter is preferable for solvent purposes. Among other solid solvents may be mentioned camphor. Fusel oil and also refined amyl alcohol, amyl acetate and other amyl esters such as amyl lactate may be used in some. cases. Butyl alcohol is not so heavy a solvent but its odor and also the odor of fusel oil and amyl alcohol is usualy objectionable if the amount present is substantial. Propyl alcohol and isopropyl alcohol stand intermediate the heavy solvents and the light solvents. Anisol, phenetol and chlorhydrins also may be noted as heavier solvents for addition to compositions such as indicated above.

For example referring to the composition made by mixing 60 parts by volume of trichlorethylene, 25 volumes of ethyl acetate and 15 parts of monochlorbenzol with sufficient wax to exert the desired film forming action the following compositions were made. To 8 parts by volume of the stock solution, 2 parts of aniline were introduced. This did not materially change the inflammability but the composition acted as a fairly eihcient remover. In another case 9 parts of stock solution were mixed with 1 part of tar. acids. In another case 8 parts of the stock solution were mixed with 2 parts of tar acids, the mixture had better noninflammable qualities than in the case where aniline was used. In another case 1 part and 2 parts of paradichlorbenzol were added to 9 parts and 8 parts respectively of the stock solution. This mixture catches fire on applying a flame but goes out as soon as the flame is removed, the combustion does not spread. Removers also were made by adding 1 part of anisol and also 1 part of phenetol to the stock solution. The phenetol composition appears to be slightly more diflicult at ignition than that containing anisol. A11 excellent sufiiciently noninflam1nable. remover was made from 9 parts of stock solution and 1 part of anhydrous chlorhydrins, these being agnixture of ethylene and propylene chlorhydrins. 7 volumes of the stock solution and 3 volumes of anhydrous chlorhydrin gave a remover of an improved degree of non-inflammability.

In connection with the matter of propor inflaable solvent the following may be noted with respect to ethyl acetate:

Ethyl acetate with acetylene tetrachloride- 20% dashes and burns.

30% flashes and burns.

40% flashes but not so readily.

50% does not flash but will burn.

60% ignites.

7 0% will not ignite.

The criticism of a composition made up of 30% ethyl acetate and acetylene tetrachloride is that the odor of the latter in such a predominating amount is objectionable and as acetylene tetrachloride is fairly costly on a volume basis the composition is expensive. Also 70% of acetylene tetrachloride is likely to exert too great a solvent action on wax so that a large proportion of the latter is required.

Ethyl acetate with carbon tetrachloride- 30% flashes and burns.

40% ignites and burns with a smoky flame.

50% will not ignite.

While only 50% of carbon tetrachloride is used in this case showing that the latter is more powerful in suppressing inflammability than acetylene tetrachloride it should be noted that carbon tetrachloride rather readily turns acid and attacks metal containers.

Isopropyl alcohol with acetylene tetrachlor1de- 30% flashes and burns.

40% ignites readily.

50% ignites but less readily.

60% willjust ignite.

65% will not ignite.

Isopropyl alcohol with carbon tetrachloride- 20% ignites.

30% will not ignite.

In order to determine whether paradi chlorbenzol would result in raising the flashpoint of these mixtures a mixture of 50% ethyl acetate, 50% acetylene tetrachloride was saturated with paradichlorbenzol (60 to 7 0% of the weight of the solvent), this was found to burn just as readily as before the addition of the paradichlorbenzol. A mixture of 60% ethyl acetate, 40% carbon tetrachloride was saturated with paradichlorbenzol (about 80% of the Weight of the solvent), this was found to burn equally as readily as before the addition of dichlorbenzol.

Orthodichlorbenzol as stated is a liquid and is non-inflammable and combustible with great difliculty. When mixed with benzyl alcohol which also is very diliicult to ignite a mixture is obtained which may be used as a paint and varnish remove-r and Which is practically free from any criticism of inflam mability. Owing to the slow eva orating properties of these solvents the ad ition of wax is not necessary in many cases. Such a remover, however, is so slow in its action that it does not give commercially satisfac tory results as a rule. If a composition such as is now generally used for paint'and varnish removing purposes consisting of benzol and acetone or alcohol with wax be taken as a standard for comparison, e. g. a mixture of equal parts by volume of benzol and methyl acetone with which is incorporated 5% of paraflin wax. the speed of softening paint or varnish may be represented by the figure 1. lVhile in the case of the mixture of orthodichlorbenzol and benzyl alcohol the figure will be from 3 to 5. denoting that I) to 5 times as long a period is required to remove the same coating of paint or varnish as is requisite with the standard benzolacetone remover. The addition of ethyl alcohol or better methyl ethyl ketone or ethyl acetate materially increases the speed of the above mentioned benzyl alcohol composition but makes the latter readily inflam mable. A volatile chlorinated solvent may therefore be added proportionate in amount to the amount of volatile inflammable solvent. From the foregoing it will be noted that certain ratios of carbon tetracl'iloridc, acetylene tetrachloride or trichlorethylene to other volatile inflammable solvents are required to suppress the inflammability of the latter. This ratio should be substantially preserved in the presence of heavy solvents such as benzyl alcohol or orthodichlorbenzol as the effect of the latter on reducing the inflammability of the higher volatile solvent is small. Of the heavy solvents phenol and cresol appear to have the greatest effect but this is not sufliciently high in view of the relatively small proportion of such carbolic acid material as may be ordinarily used in a remover to permit of the use, of phenol or cresol as deterrents of inflammability, at least to any material extent. Reliance must be had in such cases on non-inflammable solvents of a volatile nature such as the chlorinated compounds referred to above.

Orthodichlorbenzol is a substantially less inflammable vehicle than the monochlorbenzol. \Vhile the latter is ignited after a flame has been held for only a short time in contact with a horizontal surface moistened with the latter solvent it is quite diflicult under these conditions to ignite the dichlor compound.

A composition made with 50% by volume of trichlorethylene, 25% of benzyl alcohol and 25% of ethyl alcohol with approxi mately 5% of paraffin wax while a fairly safe remover to use is nevertheless ignited after a short application of a flame. On reducing the ethyl alcohol to 20% and increasing the benzyl alcohol to 80% a com position is obtained which has a sufficiently high fiashpoint to be of general utility.

Ethyl alcohol is however not as good a sol-.

highly eflicient paint and varnish remover is obtained which in comparison with the standard inflammable type of benzol-acetone remover has a speed rating of between 1 and 1.5, thus this composition while safe to use has the speed requisite for commercial application. It does not contain any undue amount of wax so that useful solvent material is not displaced by non-solventwax and the odor is not disagreeable. hen the composition is modified to 10% ethyl acetate, 80% benzyl alcohol and 60% of trichlorethylene, with approximately the same amount of wax, a very safe composition is secured which is practically incombustible. It is extremely difficult to ignite such a composition when applied to a paintedsurface and even on boiling the composition the vapors do not burn violently, nor do they set fire to the liquid itself. Thus a composition containing trichlorethylene or similar chlorinated solvent in excess, a lesser amount of a heavier solvent such as benz 1 alcohol or diacetone alcohol or chlorhydrln or mixtures of such heavy solvents and a still smaller amount of an inflammable volatile solvent, preferably boiling between 75 C. and 100 (1., as for example ethyl alcohol, ethyl acetate, methyl ethyl ketone, propyl or isopropyl alcohol may be employed in making suitable paint and varnish removing compositions of the requisite degree of noninflammability and especially in the case of compositions containing ethyl acetate or methyl ethyl ketone also possessing a rate of softening or removing action comparable Wlllfil standard inflammable remover as aforesal Solvent naphtha may be used as an extending medium in some cases but it is not a very effective solvent and ordinarily is not recommended for an active remover, its principal utility is as a cheapening and bulking agent. Propyl or isopropyl acetate or other esters may be employed in: some cases. On the other hand isopropyl ether is not recommended for non-inflammable compositions as it has too low a flashpoint. In this respect it is like acetone or methyl alcohol, the presence of which to the extent of 5% or so is very quickly indicated by the lowering of the flashpoint of the com: position necessitating increased amounts of a more costly non-inflammable solvent such as acetylene tetrachloride or trichlorethylone. As indicated above, too large a proportion of a hydrocarbon solvent or chlorinated solvent having a strong solvent action on wax throws the composition out of balance and the removing action is not as effective as when more of compounds of a generally alcoholic nature are present; this including not only the alcohols themselves but esters, ketones and the like which have a generally precipitating or non-solvent action on waxy material.

The addition. of selenium oxychloride to the above compositions is not precluded and this material has considerable solvent action on paint and varnish, however its generally acid nature makes it ordinarily undesirable, it being one object, inv the preferred form ofthe present invention, to produce a removing composition of a substantially neutral character which will not injurethe wood or the hands of the users, destroy paint brushes or corrode the metal containers.

In a number of useful formulae made in accordance with the present invention and involving a heavy solvent in conjunction with readily volatile solvents, as for example benzyl alcohol as a heavy solvent, ethyl alcohol or ethyl acetate as a volatile inflammable solvent, and trichlorethylene as a volatile non-inflammable solvent, the proportion of the trichlorethylene may be approximately 2} times that of the volatile alcoholic solvent.

The exact proportions however required to meet the requisite degree of non-inflammability vary to some extent with the general character of the solvents employed, as for example 50 parts by volume of trichlorethylene, 30 parts of diacetone alcohol and 20 parts of ethyl acetate may be ignited on contlnued application of a flame, while parts of trichlorethylene, 30 parts diacetone alcohol and 10 parts of ethyl acetate is not readily inflammable.

50 parts of trichlorethylene, 30 parts of orthodichlorbenzol and 20 parts of ethyl acetate is more readily ignited.

Among the waxes which may be employed to advantage in the above composition, in order to prevent or minimize evaporation, are parafiin and ceresin wax. The former is better for liquid remover while the latter in suflicient proportion gives a pasty remover of smooth consistency. Other waxes such as beeswax, carnauba, montan, candelila wax and the like may be added to the foregoing waxes or used by themselves but are not as satisfactory as paraflin wax. Thickening agents such as soaps, nitrocellulose, cellulose acetate and the like may also be used in some cases.

What I claim is 1. A paint and varnish removin composition adapted for softening drie films of paint and varnish which comprises a mixture of solvents including a volatile inflammable solvent and a volatile non-inflammable solvent, comprising trichloreth lene, the proportion of said non-inflamma 1e solvent being suflicient to suppress the inflammability of the former so that the composition when contacted With a flame does not readily ignite and propagate a dangerous combustion; the composition containing wax suflicient in amount to serve as an eificient evaporation-retarding substance for the volatile solvents but said wax not being suflicient in quantity to displace a material amount of the volatile solvents; said composition being capable of softening dried coats of paint and varnish at a rate not materially slower than inflammable paint and varnish remover made. from equal volumes of benzol and acetone with about 5% of wax.

2. A paint and varnish removing com position adapted for softening dried films of paint and varnish which comprises a mixture of solvents including a volatile inflammable solvent and majorproportion of a volatile non-inflammable solvent comprising trichlorethylene, the proportion of said non-inflammable solvent being sufiicient to suppress the infiammability of the former so that the composition when contacted with a flame does not readily ignite and propagate the combustion; the composition containin Wax suflicient in amount to serve as an e cient evaporation-retardin substance for the volatile solvents but sald wax not being suflicient in quantity to displace a material amount of the volatile solvents; said composition being capable of softening dried coats of point and varnish at a rate not materially slower than inflammable paint and varnish made from equal volumes of benzol and acetone with about,5% of wax.

3. A paint and varnish removing com position adapted for softening dried'films of paint and varnish which comprises amixture of solvents including a volatile inflammable solvent boiling between and 100 0., and a volatile non-inflammable solvent comprising trichlorethylene, the proportion of said non-inflammable solvent being sufiicient to suppress the inflammability of the former so that the. composition when contacted with a flame does not readily ignite and propagate the combustion; the composition containing wax suflicient in amount to serve as an efiicient evaporation retarding substance for the volatile solvents but said wax not bein sufiicient in quantit to displace a material amount of the v0 atile solvents; said composition being capable of softening dried coats of paint and varnish at a rate not materiall slower than inflammable paint and varmsh' remover made from equal volumes of benzol and acetone with about 5% of wax.

s 4; A paint and varnish removing composition adapted for softening dried films of paint and varnish which comprises a mixture of solvents including a heavy solvent, a volatile inflammable solvent boiling under 100 (1., and at least an equal proper tion of a volatile non-inflammable solvent, the proportion of the latter being sufficient to suppress the inflammability of the former so that the composition when contacted with a flame does not readily ignite and propagate the combustion; the composition containin Wax sufiicient in amount to serve as an e cient evaporation retarding substance for the volatile solvents but said wax not being sufficient in quantity to displace a material amount of the volatile solvents; said composition being capable of softening dried coats of paint and varnish at a rate at least two-thirds as rapidly as inflammable paint and varnish remover made from equal volumes of benzol and acetone with about 5% of wax.

5. A paint and varnish remover comprising wax, trichlorethylene, dia-cetone alcohol and ethyl acetate;

6. A paint and varnish remover consisting of wax, trichlorethylene, an alcohol and a volatile solvent whose boiling point is above 75C. and not excedeing 100 C.

7. A paint and varnish remover consisting of wax, trichlorethylene, a heavy alcohol and an ester Whose boiling point is above 75 C. and not exceding 100 C.

8. A paint and varnish remover comprising wax, trichlorethylene, diacetone alcohol and a volatile alcoholic solvent whose boiling point is above 75 C. and not exceeding 100 C.

In testimony whereof, I have signed this specification.

CARLETON ELLIS. 

